1. Field of the Invention
The present invention relates to a peripheral simulation system for emulating real peripheral devices during the testing of tactical programs, but more specifically it relates to an Externally Specified Index (ESI) peripheral simulator for converting the signals of a simulation computer to be compatible with an operatively connected tactical computer.
2. Description of the Prior Art
In the prior art, simulation programs have been developed to test, for example, fire control programs in a realistic environment before being installed on ships. The simulation program supplies the fire control system with all of the data needed for the proper testing thereof. Thus, programmers can test tactical programs under actual conditions while still in the laboratory.
Notwithstanding the foregoing, a compatibility problem arises when, for example, a simulation computer which communicates through intercomputer input/output ports is used to test, for example, a Mark 92 Fire Control System, a tactical computer which interfaces via (ESI) peripheral input/output ports as specified in MIL-STD-1397 (SHIPS) Aug. 30, 1973. Consequently, there is a need in the prior art for an ESI peripheral simulator to be configured to interface between a simulation computer and a tactical computer in an improved manner.
There are two alternatives to the use of an ESI peripheral simulator according to the present invention. The first is the modification of the tactical computer program. This is not a practical alternative since the characteristics, functional and timing, of the input/output interface would be changed. Hence, a true operational test of the tactical program cannot be made. Thus, there is a need in the prior art to provide true operational testing of the tactical computer's program.
The second alternative is to use the actual tactical peripheral equipment connected to the tactical computer. This is not a practical approach either since every test and development site would require a full set of peripherals. Consequently, there is a need in the prior art to eliminate the necessity for a full set of peripherals at every development test site.
As further background material, in one embodiment of U.S. Pat. No. 3,932,843, filed Nov. 23, 1973, to Trelut et al, entitled, "Real-time Control Arrangement for a Simulation Device", is disclosed a simulation system configured for the development of a program to be used in a real-time operated system including a first computer and a second computer operating on a load-sharing basis. A simulation device including a simulation computer (third computer) and a simulation interface is coupled to the first and second computers to simulate their peripheral equipment by exchanging with the first and second computers data which would normally be exchanged between the first and second computers and their peripheral equipment. The simulation interface performs the aforementioned data exchanges between the first and second computers and the simulation computer. The simulation interface includes a time control arrangement for synchronizing the data exchanges and a memory arrangement for temporarily storing exchanged data.
In Trelut et al, the invention is directed towards a system for simulating real-time system peripheral equipment by exchanging with two time sharing (load sharing) computers and a third simulation computer, data which is normally exchanged between the time sharing computers and their actual peripheral equipment. This system is configured to transfer data in one direction across its simulation interface. There is no teaching, inter alia, of bi-directional transfer of information as taught in the present application.
Consequently, there is a need in the prior art to control the transfer of information, both actual data and commands, bidirectionally between a tactical computer and a simulation computer to provide true operational testing of the tactical computer's programs while simulating the actual tactical peripheral equipment that would normally be connected to the aforementioned tactical computer. This bi-direction transfer of information should include the interleaving of actual data and commands, i.e., command words should be interdispersed with actual data words.
The prior art, as indicated hereinabove, include advances in computer simulation devices and systems including devices and systems for simulating the peripheral equipment of a real-time system. However, insofar as can be determined, no prior art peripheral simulating system incorporates all of the features and advantages of the present invention.